Screen printing method and holding table for plate to be printed

ABSTRACT

A printing agent within a through hole of a screen is smoothly and completely released out when separating the screen from a plate to be printed. 1. In a screen printing method, at a time of applying a printing agent to a plate to be printed by a movement of a squeegee, the plate to be printed is gradually separated from said screen from one side of the screen to the other side thereof step by step during a movement of the squeegee to a movement finishing end.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a screen printing method and aholding table for a plate to be printed used for the method.

[0003] 2. Description of the Prior Art

[0004] A screen printing is so structured as to move a squeegee in astate of bringing a screen into contact with an upper surface of a plateto be printed such as a printed plate board and the like or setting thescreen slightly apart therefrom and apply a printing agent such as acreamed solder and the like to the plate to be printed, therebyperforming a printing.

[0005] Further, during the process, the screen is separated from theplate to be printed after applying the printing agent. In this case, thescreen is conventionally wholly lifted up to an immediately upperdirection and all the surface is separated simultaneously from the plateto be coated.

[0006] However, when all the surface is simultaneously separated asmentioned above, there is a case that the printing agent within athrough hole of the screen is left within the through hole without beingreleased out over the printed plate board, especially at the moment thescreen is separated at a center portion thereof, depending upon a degreeof a viscosity of the printing agent. In this case, an uneven coating ofthe printing agent on the plate to be printed is generated, so that aproblem that a lack of pattern is generated. For this reason, in orderto peel off the uneven printing agent conventionally, a peelingoperation is performed for ten and some minutes.

[0007] Therefore, a lot of producing time is required by the time ofcompletion, and this greatly causes to increase a cost of a product.

SUMMARY OF THE INVENTION

[0008] The present invention is made by taking the points mentionedabove into consideration, and an object of the present invention is toprovide a screen printing method structured so that a printing agentwithin a through hole of a screen may smoothly and completely releaseout when separating the screen from a plate to be printed, therebypreventing a uneven coating of the printing agent from generating.

[0009] Another object of the present invention is to provide a screenprinting method structured so as to move a squeegee with a properinterval between a screen and a plate to be printed, in which a printingcan be performed by keeping the same interval from the first to the lastprinting operation.

[0010] Still further, the other object of the present invention is toprovide a holding table for a plate to be printed which is so structuredas to efficiently perform the screen printing method mentioned above.

[0011] In accordance with a first aspect of the present invention, thereis provided a screen printing method, in which at a time of applying aprinting agent to a plate to be printed by a movement of a squeegee, theplate to be printed is gradually separated from said screen and from oneside of the screen to the other side thereof step by step during amovement of the squeegee to a movement finishing end.

[0012] Further, in accordance with a second aspect of the presentinvention, there is provided a screen printing method, in which at atime of applying a printing agent to a plate to be printed by a movementof a squeegee, the plate to be printed is gradually separated from saidscreen and from one side of the screen to the other side thereof step bystep after the squeegee reaches a movement finishing end.

[0013] Still further, in accordance with a third aspect of the presentinvention, there is provided a screen printing method which is sostructured as to move a squeegee at a proper interval between a screenand a plate to be printed, in which at a time of applying a printingagent to a plate to be printed by a movement of a squeegee, the plate tobe printed is set below the screen in an inclined manner so that amovement starting side is most apart, and a movement finishing side ofthe squeegee of the plate to be printed is gradually descended incorrespondence to a moving speed of the squeegee to thereby always keepprinting at the same interval.

[0014] Furthermore, in accordance with a fourth aspect of the presentinvention, there is provided a screen printing method which is sostructured as to move a squeegee at a proper interval between a screenand a plate to be printed, in which at a time of applying a printingagent to a plate to be printed by a movement of a squeegee, the plate tobe printed is set below the screen in an inclined manner so that amovement starting side is most apart, and the plate to be printed isgradually descended while keeping an angle of incline in correspondenceto a moving speed of the squeegee to thereby always keep printing at thesame interval.

[0015] Moreover, the screen printing method in accordance with thefirst, second and third aspects mentioned above of the prevent inventioncan be efficiently realized by a holding table for a plate to be printedcomprising a supporting body stood on an end on a table plate, a holdingplate setting a plate to be printed on a surface thereof, an end of theholding plate being pivotally attached to an upper end of saidsupporting body in such a manner as to freely incline, and said holdingplate being gradually inclined from a horizontal state at apredetermined speed via proper means.

[0016] Further, the holding table for the plate to be printed may bemade by the following concrete structure. Accordingly, there is provideda holding table for a plate to be printed, comprising a table plate, asupporting body stood on an end on said table plate, a holding platesetting the plate to be printed on an upper surface thereof and havingan end pivotally attached to an upper end of said supporting body insuch a manner as to freely incline, a link having one end side pivotallyconnected to a lower surface in a side of a free end of said holdingplate and the other end side pivotally connected to a moving table, themoving table mounted in such a manner as to freely move in a directionof attaching to and detaching from said supporting body, a driving plateadhered to said moving table and having a screw with which a screw shaftis engaged, and a reversible driving motor adhered on said table plateand making the screw shaft connected to an axis of rotation thereof toengage with the screw of said driving plate.

BRIEF DESCRIPTION OF THE DRAWINGS

[0017]FIG. 1 is a schematic view of a screen printing method inaccordance with claim 1 of the present invention;

[0018]FIG. 2 is a schematic view of a screen printing method inaccordance with claim 2 of the present invention;

[0019]FIG. 3 is a schematic view of a screen printing method inaccordance with claim 3 of the present invention;

[0020]FIG. 4 is a schematic view of a screen printing method inaccordance with claim 4 of the present invention, which shows a statethereof before starting printing;

[0021]FIG. 5 is a schematic view of the screen printing method inaccordance with claim 4 of the present invention, which shows a state atwhich a squeegee moves and starts applying a printing agent to a plateto be printed;

[0022]FIG. 6 is a schematic view of the screen printing method inaccordance with claim 4 of the present invention, which shows a state atwhich the squeegee moves in the middle of the plate to be printed;

[0023]FIG. 7 is a schematic view of the screen printing method inaccordance with claim 4 of the present invention, which shows a state atwhich the squeegee moves near an, end portion of the plate to beprinted;

[0024]FIG. 8 is a front elevational view of a holding table of the plateto be printed in accordance with the present invention;

[0025]FIG. 9 is a plan view of a holding table of the plate to beprinted in accordance with the present invention;

[0026]FIG. 10 is a left side elevational view of a holding table of theplate to be printed in accordance with the present invention; and

[0027]FIG. 11 is a right side elevational view of a holding table of theplate to be printed in accordance with the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT

[0028] An embodiment in accordance with the present invention will bedescribed below.

[0029] First, a description will be given of an embodiment of a screenprinting method in accordance with claim 1 of the present invention withreference to FIG. 1. A state shown by a solid line in FIG. 1 correspondsto a state at which a squeegee 1 is moved and a printing agent 2 such asa creamed solder or the like is applied to a plate 3 to be printed suchas a printed plate board or the like. In this case, in order to promotean understanding, the other elements in a screen printing machine areomitted.

[0030] The present invention is characterized in that the squeegee 1gradually inclines the plate 3 to be printed at a predetermined speed asshown by an imaginary line during a movement to a movement finishing endso as to gradually separate the plate 3 from one side of a screen 4 tothe other side thereof step by step.

[0031] Further, an embodiment of a screen printing method in accordancewith claim 2 of the present invention is shown in FIG. 2. A differencefrom the embodiment shown in FIG. 1 is that the plate to be printed isseparated from the screen after the squeegee reaches a movementfinishing end. In this case, since the other elements are the same asthose in FIG. 1, the same reference numerals are used to the sameelements, and a description thereof will be omitted.

[0032] Still further, FIG. 3 shows an embodiment of a screen printingmethod in accordance with claim 3 in a screen printing method which isso structured as to move a squeegee at an interval between a screen anda plate to be printed, which is different from that of FIGS. 1 and 2. Inthis case, the plate 3 to be printed is set in an inclined manner sothat a movement starting side of the squeegee is most apart to therebygradually descend the movement finishing end of the squeegee in theplate 3 to be printed in correspondence to a moving speed of thesqueegee.

[0033] Furthermore, FIGS. 4 to 7 show an embodiment of a screen printingmethod in accordance with claim 4 in a screen printing method which isso structured as to move a squeegee at an interval between a screen anda plate to be printed, which is different from the printing method shownin FIG. 3. In this method, the plate 3 to be printed is set below thescreen 4 in an inclined manner so that a movement starting side of thesqueegee 1 is most apart to thereby gradually descend the plate to beprinted in correspondence to a moving speed of the squeegee whilemaintaining an angle of incline.

[0034]FIG. 4 shows a state before starting a printing, FIG. 5 shows astate that the squeegee 1 moves and starts in applying the printingagent 2 to the plate 3 to be printed, FIG. 6 shows a state that thesqueegee 1 moves in the middle of the plate 3 to be printed, and FIG. 7shows a state that the squeegee 1 moves near an end portion of the plate3 to be printed.

[0035] Second, a description will be given of a holding table for theplate to be printed shown in FIGS. 8 to 11.

[0036] In the drawings, reference numeral 5 denotes a holding table forthe plate to be printed, which is constituted by the following elements.Further, the holding table 5 for the plate to be printed receives theplate to be printed such as a printed plate board or the like from aconveyor (not shown), ascends the plate to be printed to a positionwhere it comes in contact with a lower surface of the screen and is seton an ascending and descending table (not shown) which descend againafter printing.

[0037] Reference numeral 6 denotes a rectangular table plate. Referencenumerals 7, 7 denote supporting bodies stood on an end of the tableplate 6. Reference numeral 8 denotes a holding plate for setting theplate to be printed on an upper surface, in which an end is pivotallyattached to an upper end of each of the supporting bodies 7 and 7 insuch manner as to freely incline. Reference numerals 9, 9 denotesupporting bodies adhered to an end of the holding plate 8, andreference numeral 10 denotes a shaft for pivotally attaching each of thesupporting bodies 9 and 9 to the upper end of each of the supportingbodies 7 and 7 in such a manner as to freely incline.

[0038] Reference numeral 11 denotes a link, in which an end is pivotallyconnected to a lower surface on a side of a free end of the holdingplate 8 and the other end is pivotally connected to a moving tablementioned below. Reference numeral 12 denotes a member for connecting anend of each of the links 11 and 11 to the free end of the holding plate8, which is adhered to the lower surface on the side of the free end ofthe holding plate 8. Reference numeral 13 denotes a shaft for pivotallyconnecting each of the links 11 and 11 to each of the members 12 and 12.Reference numeral 14 denotes a shaft for pivotally connecting the otherend of each of the links 11 and 11 to the moving table.

[0039] Reference numeral 15 denotes a guide rail, and the guide rails 15and 15 are provided on the table plate 6 in a parallel manner. Further,the guide rails 15 and 15 are provided on a side opposite to thesupporting bodies 7 and 7. Reference numeral 16 denotes a moving tablemounted to each of the guide rails 15 and 15, which is structured so asto freely move in a direction of attaching to and detaching from thesupporting body 7.

[0040] Reference numeral 17 denotes a driving plate extending betweenthe moving tables 16 and 16 and adhered thereto, which is provided witha screw (not shown) engaging with a screw shaft mentioned below at amiddle portion in a longitudinal direction. Reference numeral 18 denotesa reversible driving motor adhered on the table plate 6, in which aservo motor is used in the present embodiment. Further, a screw shaft 19is connected to an axis of rotation of the driving motor 18, and thescrew shaft 19 is engaged with the screw provided in the driving plate17.

[0041] Then, the holding table 5 for the plate to be printed is operatedin the following manner.

[0042] In the case of printing in accordance with the printing methodshown in FIG. 1 and 2, the holding plate 8 is positioned in a horizontalmanner as shown in FIG. 8. When the printing agent is applied to theplate to be printed by a movement of the squeegee, the driving motor 18is operated. In this case, the operation of the driving motor 18 may beperformed after the printing is completely applied to all the surface ofthe plate to be printed, or may be performed immediately after thesqueegee passes in the middle of the printing and performs anapplication, thereby starting an peeling operation.

[0043] When the driving motor 18 is operated, the holding plate 8 startsin inclining around the shaft 10 as a supporting point. In this case,when the driving motor 18 is operated, the screw shaft 19 is rotated,and the moving table 16 is moved via the driving plate 17. Then, theholding plate 8 is inclined via the link 11 in accordance with amovement of the moving table 16. Inclining of the holding plate 8 isslowly performed, and the rotational speed of the driving motor 18 isadjusted so that the holding plate 8 is inclined at a proper speed incorrespondence to a viscosity of the printing agent or the like.

[0044] When the holding plate 8 is inclined, the plate to be printed seton the upper surface of the holding plate 8 is gradually separated offthe screen from a side of the screen to the other side step by step.When the plate to be printed is separated in the manner mentioned above,the plate to be printed is slowly peeled off by a uniform force and thescreen is separated while being obliquely bent, so that the printingagent within the through hole of the screen can be easily released fromthe through hole.

[0045] When the squeegee reaches the movement finishing end and theprinting is completed, the ascending and descending table is droppeddown. At this time, the driving motor 18 is reversely rotated so as toreturn the holding plate 8 to a horizontal state again. When theascending and descending table is dropped down so as to release theplate to be printed in the printing agent and the next plate to beprinted is set, the ascending and descending table is again lifted up soas to perform a printing. Then, the operation mentioned above isperformed thereafter.

[0046] In accordance with the methods as cited in claims 1 and 2 of thepresent invention, the printing agent within the through hole of thescreen can be smoothly and completely released out when separating thescreen from the plate to be printed. Accordingly, it is possible toprevent a uneven coating of the printing agent from generating.

[0047] Further, in accordance with the methods as cited in claims 3 and4 of the present invention, in the screen printing method which is sostructured as to move the squeegee with an interval between the screenand the plate to be printed, a printing can be performed in a state ofkeeping the same interval (a length L in FIG. 3 and a length L₁ in FIGS.5 to 7) from the beginning to end. Accordingly, it is preferable to aprinting of a special printing agent other than the creamed solder, andfurther it is possible to print a required necessary amount. Stillfurther, a large number of printings can be performed without soiling aback surface of the screen.

[0048] Particularly, in accordance with the methods as cited in claims 1to 4 of the present invention, more significant effect can be obtainedin the case of printing a pattern having a high density and in the caseof using a thin screen.

[0049] Further, in accordance with the holding table for the plate to beprinted as cited in claims 5 and 6 of the present invention, it ispossible to efficiently perform the method mentioned above.

What is claimed is:
 1. A screen printing method, wherein at a time ofapplying a printing agent to a plate to be printed by a movement of asqueegee, the plate to be printed is gradually separated from saidscreen and from one side of the screen to the other side thereof step bystep during a movement of the squeegee to a movement finishing end.
 2. Ascreen printing method, wherein at a time of applying a printing agentto a plate to be printed by a movement of a squeegee, the plate to beprinted is gradually separated from said screen and from one side of thescreen to the other side thereof step by step after the squeegee reachesa movement finishing end.
 3. A screen printing method, wherein at a timeof applying a printing agent to a plate to be printed by a movement of asqueegee, the plate to be printed is set below the screen in an inclinedmanner so that a movement starting side is most apart, and a movementfinishing side of the squeegee of the plate to be printed graduallydescends in correspondence to a moving speed of the squeegee, therebyprinting with always keeping the same interval.
 4. A screen printingmethod, wherein at a time of applying a printing agent to a plate to beprinted by a movement of a squeegee, the plate to be printed is setbelow the screen in an inclined manner so that a movement starting sideis most apart, and the plate to be printed is gradually descends whilekeeping an angle of incline in correspondence to a moving speed of thesqueegee, thereby printing with always keeping the same interval.
 5. Aholding table for a plate to be printed comprising a supporting bodystood from an end on a table plate, a holding plate setting a plate tobe printed on a surface thereof, an end of the holding plate beingpivotally attached to an upper end of said supporting body in such amanner as to freely incline, and said holding plate being graduallyinclined from a horizontal state at a predetermined speed via propermeans.
 6. A holding table for a plate to be printed, comprising a tableplate, a supporting body stood on an end on said table plate, a holdingplate setting the plate to be printed on an upper surface thereof andhaving an end pivotally attached to an upper end of said supporting bodyin such a manner as to freely incline, a link having one end sidepivotally connected to a lower surface on a side of a free end of saidholding plate and the other end side pivotally connected to a movingtable, the moving table mounted in such a manner as to freely move in adirection of attaching to and detaching from said supporting body, adriving plate adhered to said moving table and having a screw with whicha screw shaft is engaged, and a reversible driving motor adhered on saidtable plate and making the screw shaft connected to an axis of rotationthereof to engage with the screw of said driving plate.